This invention relates to printing, and more particularly to printing designs and patterns on webs and other surfaces.
The application of designs and patterns, particularly in color, to surfaces such as webs, typified by textiles, is an art which had its beginnings in prehistory and which embraces a large number of different techniques. Examples of these techniques include the direct manipulation of the web to produce the pattern, as in tie dying, the use of stencils as in silk screen, printing plates, as in intaglio, letter-press, and planographic printing, and the direct manipulation of the coloring matter itself, as by hand painting and jet printing.
Typically, if a multi-colored design is to be produced, these techniques require that two or more colors be applied in succession. In terms of apparatus, this requires either that the device used to apply a single color be cleaned and otherwise prepared between each color, or that a multiplicity of devices, one for each color be used in succession. Generally, all successive patterns must be applied in registration, and, in the case of stencils and printing plates, a separate stencil or plate must be prepared for each color to be applied in a different pattern.
Consideration of the foregoing indicates a number of potential limitations in apparatus designed for volume production of printed designs and patterns. Registration may be difficult to insure, due to the dimensional instability of the web. Registration is particularly critical at the boundary line separating colors, and lack of registration may prevent printing patterns with fine boundaries. Practical considerations place limits on the number of separate colors which may be applied, and while this limitation to the pallette may be of little consequence in some circumstances, it can severely limit the designs which can be reproduced in other cases. In this connection, it should be noted that, for the majority of these techniques, the number of gradations in the quantity of coloring matter presented to the web in any single application of color is generally small, and that three- or four-color processes in these cases results in a very limited selection of hue, saturation, and lightness in the resulting print.
Clearly, a method of printing which permits the simultaneous application of a large number of colors to a surface, without the need of stencils or plates, has considerable application.